Panchromatic Color Filter Array Sensor for Low-Light Imaging
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Solution Overview
Problem
Current electronic imaging systems face challenges in reducing motion blur in low-light conditions without increasing noise, complexity, or memory requirements, and existing solutions either require additional hardware or are not practical for conventional cameras.
Innovation Solution
A method involving a color filter array image sensor with both color and panchromatic channels, where the panchromatic channel is captured with a different exposure time than the color channels, allowing for interpolation to produce a full-color output image with reduced motion blur, eliminating the need for a flash or complex stabilization systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If exposure time is lengthened to gather more light in low-light conditions, then image brightness is improved, but motion blur increases
Solution Approach 1:
The image sensor is segmented into color filter array pixels and panchromatic pixels, with each type capturing light differently. The panchromatic pixels capture full-spectrum light with higher efficiency, allowing shorter exposure times while maintaining brightness, thus reducing motion blur.
Solution Approach 2:
The patent changes the spectral sensitivity parameter of specific pixels by removing color filters to create panchromatic pixels. This parameter change allows these pixels to capture more light across the spectrum, enabling shorter exposure times without sacrificing image brightness.
2Manufacturing precision
If exposure time is shortened to reduce motion blur, then image sharpness is improved, but image brightness deteriorates
Solution Approach 1:
The sensor array is divided into color pixels and panchromatic pixels. Panchromatic pixels are strategically placed to capture sufficient light signal even at short exposure times, enabling the use of brief exposure intervals while maintaining adequate brightness in the final image.
Solution Approach 2:
The panchromatic pixels perform an excessive light-gathering action compared to color-filtered pixels, capturing more photons during the short exposure interval. This excess light capture compensates for the reduced exposure time, maintaining brightness while achieving sharpness.
3Illumination intensity
If analog or digital gain is applied to brighten under-exposed images, then image brightness is improved, but image noise increases
Solution Approach 1:
The panchromatic pixels perform preliminary light gathering during the exposure interval, accumulating sufficient photon signals before readout. This preliminary action ensures that the signal is strong enough to be read out without requiring subsequent amplification, thereby avoiding noise introduction from analog or digital gain.
4Loss of energy
If high-grade optical elements with large apertures are used to preserve more light, then light transmission is improved, but device complexity and cost increase
Solution Approach 1:
Instead of changing optical parameters like aperture size, the patent changes the pixel-level parameter by removing color filters to create panchromatic pixels. This parameter change increases light transmission at the sensor level without requiring complex optical modifications, maintaining simplicity while improving light capture efficiency.
5Manufacturing precision
If a photographic flash is used to provide strong illumination and shorten exposure time, then image sharpness is improved, but device cost and weight increase
Solution Approach 1:
The panchromatic pixels serve the dual function of capturing both luminance and chrominance information, and they enable short exposure times through their superior light-gathering capability, eliminating the need for external illumination devices like flashes. The system is self-sufficient in achieving sharp images without additional hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the production of high-quality, full-resolution color images with reduced motion blur without additional noise, cost, or memory requirements, and is applicable to conventional cameras.
Implementation Method 1
a color filter array image sensor with both color and panchromatic channels, where the panchromatic channel is captured with a different exposure time than the color channels
Data Source
AI summary
A method of forming a full-color output image using a color filter array image having a plurality of color channels and a panchromatic channel, comprising capturing a color filter array image having a plurality of color channels and a panchromatic channel, wherein the panchromatic channel is captured using a different exposure time than at least one of the color channels; computing an interpolated color image and an interpolated panchromatic image from the color filter array image; computing a chrominance image from the interpolated color image; and forming the full color output image using the interpolated panchromatic image and the chrominance image.